Mobile Image Capture Algorithm for Document Distortion Correction
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Solution Overview
Problem
Mobile devices face challenges in processing digital images of documents due to limited processing power and image resolution, as well as issues with maintaining aspect ratio and dimensions, which are not effectively addressed by conventional scanner-based processing algorithms.
Innovation Solution
A mobile image capture and processing algorithm that includes edge detection, page detection, and correction for projective and non-linear optical effects, allowing for efficient processing and correction of images captured by cameras, which involves defining analysis windows and statistical estimation to identify document boundaries and correct skew and illumination issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional scanner-based processing algorithms are used on mobile devices, then document capture and processing can be performed, but the limited processing power and memory make the algorithms prohibitively expensive in terms of computational cost and processing time
Solution Approach 1:
The patent transforms the high-complexity scanner-based processing algorithms into mobile-friendly versions by changing processing parameters: using simplified edge detection methods, reducing memory requirements through efficient data structures, and optimizing computational steps to run on limited mobile hardware while maintaining document capture functionality
Solution Approach 2:
The patent extracts and removes the most computationally intensive components from conventional scanner processing algorithms, keeping only the essential functions needed for mobile document capture such as basic edge detection and simple skew correction, thereby reducing computational cost while preserving core functionality
2Ease of manufacture
If conventional scanner-based processing algorithms are used on mobile devices, then document capture can be performed, but the processing time is far too long to be practical for mobile applications
Solution Approach 1:
The patent segments the document processing into distinct stages: capture, edge detection, skew detection, and correction. Each stage uses optimized algorithms appropriate for mobile hardware, allowing parallel processing and reducing overall processing time while maintaining capture quality
Solution Approach 2:
The patent performs preliminary actions during the capture phase by pre-calibrating camera parameters and pre-processing the image data to reduce the computational burden during actual processing, thereby reducing processing time without sacrificing capture capability
3Ease of operation
If mobile camera capture is used, then portability and convenience are improved, but the device cannot faithfully represent the physical document by maintaining aspect ratio, dimensions, and shape
Solution Approach 1:
The patent implements feedback mechanisms where the system detects document boundaries and skew angles, then automatically adjusts transformation parameters to correct distortions. The processed document is compared against expected geometric properties, and corrections are applied iteratively to maintain accurate aspect ratio and dimensions
Solution Approach 2:
The patent applies dynamic geometric transformation to the captured image, using detected document boundaries to calculate and apply real-time correction factors for skew, perspective distortion, and aspect ratio maintenance, thereby preserving document geometry despite mobile camera limitations
4Adaptability or versatility
If mobile camera capture is used, then document capture can be performed anywhere, but projective effects and nonlinear distortions are introduced that are not present in scanner-based capture
Solution Approach 1:
The patent introduces an intermediary processing stage that detects and corrects projective effects and nonlinear distortions. This intermediary step uses geometric transformation algorithms to map the distorted camera image back to the original document geometry, ensuring consistent and reliable document representation across different capture conditions
Data Source
AI summary
In various embodiments, methods, systems, and computer program products for processing digital images captured by a mobile device are disclosed. The exemplary image processing techniques are coupled with inbound and outbound communications protocols and workflows configured to facilitate closed-loop processing, such that a method includes initiating a workflow; providing one or more of case information and raw data to the workflow; processing one or more of the case information and the raw data to generate a processing result; storing at least some of the case information in association with the processing result, wherein the associated case information acts as an identifier of the processing result; transmitting at least the processing result and the identifier; receiving, in response to the transmitting, a reply comprising the identifier; and retrieving at least the processing result using the identifier.